The invention relates to a plastic pedal for a motor vehicle such as a clutch pedal. The pedal includes a stepping plate portion in one piece with, and at the front end of, a pedal arm. The pedal arm has a spring lever portion with bearing bores at its rear end and the spring lever faces in a direction away from the stepping plate.
DE-A 34 27 097 shows a plastic clutch pedal for a motor vehicle with a pedal arm that is made in one piece and has ribbings arranged between two webs. These ribbings have the purpose of providing a required stiffness and absorbing the relatively high torsional and bending stresses to which the pedal is subjected during its operation. In order to meet these requirements, a pedal arm provided with a ribbing must be constructed to be very massive which results in an increase in weight and a pedal with large measurements.
The invention has an object the providing of a clutch pedal for a motor vehicle which is low in weight and one which is small in construction and high in stiffness.
According to the invention, this object is achieved by the pedal arm along its longitudinal axis consisting of a hollow profile of a polygonal cross-section with walls of approximately the same thickness which are constructed with smooth surfaces on the inside and on the outside.
It is also advantageous if, the hollow profile is constructed to have a rectangular cross-section and with a first portion extending from a bearing bore at the rear arm end to join a second portion that contains a stepping plate at the front arm end. The two portions taper until they reach a bend at the joining location.
It is also advantageous if the stepping plate forms a part of the front face wall of the hollow profile and has reinforcing ribs which are arranged above one another at the side wall to extend longitudinally with respect to the driving direction at the vehicle and which are connected with the stepping plate.
Ideally the first portion of the pedal arm has a transversely extending bearing bore for an input cylinder of the clutch. The bore is located adjacent through-opening at the rear wall of the hollow profile. The spring lever consists of a support with a U-profile-shaped cross-section which has transversely extending reinforcing ribs between its legs. The bearing bore is arranged between one reinforcing rib and the rear wall of the hollow profile and is provided with an extension sleeve at one side wall. The extension sleeve has radial reinforcing ribs supported at the side wall.
For structural strength, a transition of the first section of the pedal arm to the bend area of the spring lever and the transition of the pedal arm to the second section, each have a rounded portion respectively. Also, a surrounding internal rib is arranged in the hollow profile in the area of the bend.
It is also advantageous if the hollow profile of the pedal arm is open at its free ends and if the front arm end carrying the stepping plate is constructed to have a cross-section in the shape of a U-profile. The web of this U-profile forms a part of the stepping plate and its legs represent side walls of the hollow profile of the pedal arm.
The principal advantages achieved by mean of the invention are that a pedal is provided which is easy to manufacture according to an injection-molding method and which, because of its construction as a hollow rectangular cross-sectional profile, has such a stiffness that a bending yielding of the pedal arm is prevented even in the case of non-uniform and violent stress. As a result of the hollow profile rectangular cross-section construction relatively high torsional and bending stresses are absorbed.
Because of its small mass, the hollow profile is light and may be constructed to take up little space corresponding to available space conditions.
It is cost-effective to construct the pedal of a plastic material because during the injection molding process only two cores are used to form the two sections of the pedal arm. The two cores meet in an injection mold at the bend between the upper and lower portions of the pedal arm.
The hollow profile has a rectangular cross-section and is provided with walls of approximately the same thickness which are constructed with smooth surfaces on the inside and on the outside and which also have molded-on parts for bearings and recesses.
A stepping plate is molded on (at the end side of the pedal arm) and forms part of the hollow profile. The stepping plate is provided with reinforcing ribs to support itself at the profile in order to prevent a breaking-off of the stepping plate. A spring arm is molded onto the other end of the pedal arm to face away from the stepping plate surface. This spring arm comprises a forked end with a bearing bore.
A pedal arm made of a plastic material may be supplied for different vehicle types, since bores or openings are provided in the pedal arm and thus a pedal is created of one piece without any additional expenditures. Such a pedal arm can be used in multiple ways and significantly facilitates stock of vehicle parts.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.